Introduction to the Chain Cave: The Chain Cave is a tunnel formed by the branches of collapsing volcanic lava. There are many types of lava structures in the cave. The links of lava tunnels are mostly oval or rectangular, generally 3-6 meters wide (the widest part can reach 10-12 meters), and 1-2 meters high (the highest can reach 5 meters, the lowest is only 0.5-0.8 meters) .